Tube-rolling mill



U. MARCHI TUBE ROLLING MILL iled Jul I rwefzor y lfmomch zi 2B@ 'M u.

, ON O. ..0 3 L n M Q IOL mn n I J I N Feb. 23., 192e..

o 0W o Q D :-II: m u u i IIIII M NN ,NN

Patented Feb. 23, 1926.

UNITED STATES UMBEIvro MARCHI, oEnIvARoLo, LIGURE, ITALY.

w NBE-ROLLING MILL.`

lApplication filed July 13, 1921. Serial No. 484,524.

To all whom it may concern:

Be it known that I, UMBERTO MARCHI, a subject of the King of Italy, andresiding at Rivarolo, Ligure, Italy, have invented certain new anduseful Improvements in Tube-Rolling Mills, of which the following is aspecification.

'lhis inventlon relates to tube rolling such means and an additionalobject to provide means for permitting an exact and immediate adjustingof the upper roll with respect to the lower roll .and a rigid fixationof this roll after each displacement. i

According to .the present invention 1n order to obtain the constantfeeding of the' tubular billet a bored'block is arranged in alignmentwith the axis of the grooves of the rolls so as to be adjustable in thevertical direction but not in the horizontal direction and is fastenedon the housings of the mill so that the inner end thereof bears againstthe surface of the rolls. the said rolls at each revolution pulling thebillet along for a length equal .to the semiperipheral rolling lengthofthe rolls iu reducingva tubular portion on the billet and aresubsequently disengaged from the billet so that the latter is suddenlyadvanced for the length of the rolled portion, then stopped against themouth of the block, thus insuring an equal feeding -at .each revolutionof the rolls.

According to the present invention the adjustment of the upper roll isobtained in such a manner that its supports, which are movable withinvertical guides of the housings of the mill, are coupled by rods to twohydraulic single acting cylinders vertically mounted upon the'top of theside frames the cylinders tending to continuously maintain the upperroll in an elevated position, while a horizontal double acting hydrauliccylinder with a cross sectional area of the bore larger than the totalcross sectional area of the bores of the vertical cylinders is arrangedbetween the side frames of the mill and provided withffwedge shapedextensions situated on each side of the cross'head of its piston rod soas to move in a direction at right angles to the axis of the rolls, thesaid .extensions resting upon inclined surfaces on the supports of theupper roll so that in admitting water to the front or back of the pistonit will displace the Wedge shaped cxtensions along the inclined surfacesof the supports to lower the supports or allow themA together with theupper roll to move upwardly under the traction effect of the verticalcylinders only.

An embodiment of the invention is shown by way of example in the-accompanying drawings, in which Fig. l is a front elevation of a tubemill of the Pilger system partly in vertical section.

Fig. 2 is a vertical longitudinal section taken on line 2-2 ofFig. l,and,

Fig. 3 is a rear elevation of the' mill.

In these figures similar characters of reference indicate correspondingparts. A steel block l having a bore of-a diameter of some millimeterslarger than the outside diameter of the tube to be milled is arrangedbetween the two housings 2 of the mill and has its axis maintained inalignment With the axis of the grooves of the rollers by means of twosprings 3 which pull on the block in opposite directions. The block 1slides with its inner end on the surface of the rolls and is slidablymounted between the housings by means of two ribs 4 which are engaged bycorresponding grooves of the block and thereby prevent backward movementof theblock by reason of the blows which the same receives during therolling operation.

The rolls 5 rotating in the direction of r0- tation indicated by thearrow, pull the billet G along for a length equal to thesemiperipheral'rolling circumference of the roll and mill the billet forsuch a length. During the second semi-peripheral' circumference therolls are disengaged from the billet allowing the latter to suddenlyadvance while the rolled portion of the billet immediately passesthrough the bore of the block until the shoulder of the unreducedportion of the billet presses against the mouth ofthe block. Inrepeating this operation the semiperipheral rolling surfaceslintermittently grasp the billet, mill it, and leave it to advance untilthe whole billet is reduced to a tube. With this device an excessivefeeding of the billet is made impossible and the rolling is effected ina smooth homogeneous, and unifornrmanner without unevennesses,displacement of material and rolling jumps.

are the supports of the upper roll arranged so as to be movable uponvertical guides provided on the housings of the mill, the supports beingprovided at the top thereof with relatively large inclined surfaces. Onthe tops of the housings are vertically arranged single acting hydrauliccylinders 8 which constantly under a uniform water pressure by means ofa conduit connected at 9 so as to maintain the pistons 8 of thecylinders 8 displaced at the upper end of the piston travel. The pistonsare connected with bars 10 in turn, coupled by the rods 11 with thesupport 7. By this means the supports 7 and therefore the upper roll areconstantly kept spaced from the lower roll and thereby prevented frombeing rotated on the lower roll.V

Between the two housings there is horizontally arranged a secondhydraulic cylinder 12 with double acting piston 13. The piston rod 14 isconnected with a cross head 15 bearing laterally on projecting keyshaped extensions 16 which in their turn take their position upon theinclined surfaces of the supports 7 and fill the width between thevertical guides of these supports. The cross sectional area of the boreof the horizontal water cylinder 12 is larger than the total crosssectional area of the bores of the vertical cylinders 8.

In order to lower the upper roll which on account of the traction effortexerted on its supports by the cylinders 8 is in its highest verticalposition, water is admitted through the hole 17 in the cylinder 12. Thecrosshead 15 now causes the two wedges or tapered blocks 16 to bedisplaced along the inclined surfaces of the supports and to push thesupports downwardly. In maintaining the water pressure in this cylinderby means of the hole17 the upper roll is lowered until it rolls upon thelower one or the same is stopped as desired at any intermediate positionaccording to the quantity of water admitted and in each position givento the movable roll with these hydraulic means a perfectly rigidfixation is obtained. i

In. order to again raise the upper roll, water is admitted through thehole 18 at the other end of the cylinder and upon the other side of thepiston, ejecting the water previously admitted across the hole 17. Thewater pressure now forces the piston 13 to its retracted positionallowing the supports andthe upper roll to again rise under the tractioneffort exerted by the vertical hydraulic cylinders.

It is to be understood that the adjusting device of the upper rollaccording to the present invention instead of being applied to a tuberolling mill of the Pilger step system may also be applied to othertypes of mills.

In mills having the housings arranged relatively wide distances apart,one cylinder for each housing may be provided and in this case thesedifferent horizontal cylinders may be connected to each other likecommunicating receptacles in order to obtain contemporaneously in allcylinders the same effect on the pistons.

Having thus fully described the invention what is 4claimed as new anddesired to be secured by Letters Patent'is:

A tube rolling mill including in combination, a main support, ribsformed on said Support, rotatable grooved rollers mounted within thesupport, means for effecting a constant feeding of a billet at eachrevolution of the rollers including a block provided with a bore havinga diameter slightly larger than the exterior diameter of the tube to berolled and also provided with longitudinal grooves in the opposite sideedges thereof for slidable engagement with the ribs on the main supportand for preventing lateral movement of the block relative to therollers, the block being arranged to embrace the side surfaces of therollers, and resilient means on the main support and associated with theblock for n'iaintaining the bore of the block in alinement with the axisof the grooves of the rollers.

In testimony whereof I have signed my name to this specification.

UMBERTO MARCHI.

